The present invention relates to a printable label having a flexible display with front electrical contacts to the display.
U.S. Pat. No. 5,751,257, issued May 12, 1998 and U.S. Pat. No. 6,253,190 issued Jun. 26, 2001 to Sutherland show a system including a programmable shelf tag having a bistable liquid crystal display for displaying price data and a Universal Product Code (UPC) bar code, wherein the information programmed in the display remains on the display in the absence of power. The shelf tag has a set of synchronizing indicators and corresponding electrical contacts on the front side of the display. The shelf tag is constructed by forming patterned conductive character elements on top and bottom substrates and sandwiching a polymer stabilized liquid crystal between the patterned character elements.
The shelf tag is programmable with a hand-held device that is connected to a central computer that contains inventory and price information. The hand held device can be used to scan the synchronizing indicators to identify the location of the electrical contacts, and supplies the electrical contacts with electrical signals to write appropriate information on the shelf tag. For inventory control and price updates, the hand held device is used to first read the UPC bar code on the shelf tag. If a price needs to be updated, the hand held device is then used to write the appropriate price information into the tag.
One problem with the system as described by Sutherland is that including the UPC as a writable element on the shelf tag significantly increases the complexity and cost of the shelf tag. The resolution needed to produce UPC information requires 113 modules of data, and therefore a corresponding number of contacts on the front of the display. Generally, the UPC bar code for a product is static and does not change for the life of the product.
Another problem is that shelf tags generally include other static information such as a human readable description of the product, unit identification (e.g. per oz. or per 100 sheets). The addition of this extra static information in writable form on the shelf tag would complicate the display structure of the tag to the point of impracticality.
There is a need therefore for an improved shelf tag that avoids the problems noted above.
The need is met according to the present invention by making a programmable shelf tag that includes a display element having a single flexible transparent substrate, one or more first transparent conductors located on the substrate, a layer of polymer dispersed material located over the first conductor(s), the polymer dispersed material being responsive to an applied electric field for displaying information and having first and second optical states that are both stable in the absence of an electrical field, one or more second conductors located over the polymer dispersed layer for applying the electric field to the polymer dispersed material between the first and second conductors and a plurality of display contacts located on the backside of the display for making electrical connection to the first and second conductors of the display; the display element is mounted substrate side down in a window formed in a web of adhesive backed print medium having a die cut area around the display element to form an adhesive label that includes the display element; printing static information on the label of the print medium; a support for mounting the adhesive label includes a plurality of support contacts having first conductive portions for providing contact to the conductors of the display element and second conductive portions in an area outside the adhesive label for making electrical contact with the display from the front of the display element, the support includes a layer of conductive adhesive over the first conductive portions of the support contacts. The adhesive label is attached to the support such that the display contacts are in electrical contact with the support contacts via the conductive adhesive, whereby the first and second conductors are electrically addressable from the front side of the display assembly.
The present invention allows a completed sheet with displays attached to be sold to retail outlets. Retailers can buy the completed sheet and supports, print the static information on the sheet, detach the printed labels from the sheet and affix them to the support. When a price changes, the display on the label can readily be updated, leaving the static information unchanged.